preparation and characterization of sulfobutyl ether beta-cyclodextrin binary inclusion complexes of bosentan with enhanced bioavailability

Abstract: bosentan (bos), an endothelin receptor antagonist, presents poor solubility in water, low bioavailability and side effects [1]. the aim of this study is to enhance the solubility and bioavailability of bos and its antioxidating activity through complexation using sulfobutylether-β-cyclodextrin (sbe-β-cd), which is used as a delivery material. the formation of this novel inclusion complex of bos and sbe-β-cd was synthesized and investigated in two states. solid state of complex was obtained through freeze drying and assessed by the formation of inclusion complexes was characterized by fourier transform spectroscopy (ftir), ultraviolet-visible (uv-vis) and nuclear magnetic resonance (nmr) spectroscopies [2]. the job’s method was performed to illustrate that bos was intended to form a 1:1 complex with ligand. the phase solubility study conducted in distilled water was carried out to acquire the stability constant. phase solubility analysis showed al-type diagram, according to the higuchi and connors method [3]. the solubility and dissolution of complex was significantly improved in the contrast with the bos alone as the pure drug. in addition, the results of this study confirm the formation of inclusion complex in solution. furthermore, the antioxidant activity was investigated by using dpph (2,2-diphenyl- 1-picrylhydrazyl) indicator with its violet color. the antioxidant activity of bos and the inclusion complex indicated that the inclusion complex was more reactive than its free form into antioxidant activity [4]. the interactions of complex were investigated in the presence and absence of chitosan as a carrier for delivery of drug.